In the conventional truck conveyors for the conveyance of long articles, trolleys are mounted in a projecting manner in front and in the rear of a truck as is described in Japanese Patent Publications Nos. 38391/1972, 15272/1978 and 15273/1978. In the truck conveyor disclosed in the patent publication No. 38391/1972, however, plural trolleys are all integrally connected by a connecting bar (40) and the overall length thereof is larger than the truck, so that a great increase in the storage area for this traction trolley unit is unavoidable. Moreover, in the truck conveyors disclosed in the patent publications Nos. 15272/1978 and 15273/1978, a leading trolley 14 and a trailing trolley 15, though not directly connected, are connected respectively to the front and rear portions of a truck through a connecting bar 12, so that the truck and the trolleys are not easily separable from each other, and therefore, when only the trolleys are to be stored, it is necessary to perform the operation for disconnection between the connecting bar or the truck and the trolleys.